[Pathogenesis of pneumosinus maxillaris dilatans].

Pneumoceles are most often found in the frontal sinus. Only four maxillary sinus pneumoceles have previously been reported: we add a fifth. By measuring antral pressures through a transoral puncture, we could demonstrate a valve between the nasal cavity and the maxillary antrum. Increased pressure after noseblowing is considered responsible for the maxillary sinus expansion.